The study on the residence time of cave drip water responding to the rainfall is important for accurate interpreting the meaning of the climate and environmental index in cave speleothems. For the difference of research scales and techniques, it is not paid enough attention to in the past. So this paper introducedto the tracer test technique often used in hydrogeology for cave residence time research, and made the Xiaoyan Cave in Yaji Experimental Site, Guilin, for an example. It improved the resolution in cave drip water monitoring, by using GGUN-FL30 in-situ flow-through fluorometer and tracer uranin. Based on twice tracer tests, we determined the residence time of perennial drip site XY5 in Xiaoyan Cave is less than 48 hour in rainy season, and even less than 4 hour in some rainstorm events. Meanwhile, the drip water temperature can be used as a tracer for rainfall which can produce groundwater runoff in high resolution monitoring. The runoff can be monitored when the daily rainfall is up to 16.3mm. At least two recharge sources can be identified, one is perennial base flow and the other is fast groundwater runoff produced by rainfall.